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How to read pedigrees

There’s a neverending discussion as to what can be read from a pedigree. We don’t have any definitive answers, but would like to give some insight into what we have chosen to show in pedigrees at iwdb.org, and a general primer into the practices used around the world.

The pedigree itself lists ancestors of the dog in question. It’s the blueprint which may tell you what to expect when it comes to how the dog looks and behaves, but also which diseases you may expect and what longevity you may reasonably hope for. Pedigree-information is the most important tool you have for breeding quality dogs.

In iwdb.org there’s also tons of information that will help breeders do breedings that’s good for the breed instead of damaging it’s genetic distribution.

We have added Contribution of Blood as a value in the ancestor-listings of IWDB. Interpreting these data is something some people are very used to, while it’s unknown territory for others.

Contribution of blood is an estimation of the genetic contribution made to an individual by a specific ancestor. It is given as a percentage. The base theory is that each of the parents contribute half of the genetic makeup for the offspring (50%). Each grandparent contribute a quarter (25%) each, and so on.

For each generation, the total contribution totals 100%. For each generation we go back, any single ancestor’s genetic contribution thus gets less important. A dog 10 generations back contributes less than a tenth of 1% of its genetic material to the present generation.

The contribution of blood should not be interpreted as giving a precisely accurate measure of the genetic contribution in a hound. In these calculations, the whole of generation 10 seems to be as influential as the parents. That’s not how these things work.

Look at the contribution table below, there is a cumulative effect of each generation. Each parents 50% contribution is made up of 25% from each grandparent, which is made up of 12.5% from each great-grandparent, and so on back through the generations.

Contribution-table

Generation

Contribution pr appearance

1

50%

2

25%

3

12.5%

4

6.125%

5

3.063%

6

1.563%

7

0.781%

8

0.391%

9

0.195%

10

0.098%

How can I use this?

These values are useful to see which dog is more influential in a certain breeding-program. This is especially true if the breeder is linebreeding. Then one of the more interesting questions is “who are you linebreeding on?”. The contribution of blood will give a good answer to this question. Look for the hounds with high percentage in common ancestors.

If a dog’s parent is also a grandparent on the other side of the pedigree then we can see that this ancestor has contributed 75% of the genetic make up of the dog. It’s not so easy to calculate when an individual appears twice in the 4th generation, 3 times in the fifth generation and once in the 6th generation. Or if she appears 12 times in the 8th generation, 8 times in the 9th and 7 times in the tenth. It’s a very handy way to see genetic influence without having to calculate all of this yourself. When we get way back in the pedigree, it’s quite common that certain dogs appear many times in many generations, making it hard to calculate. Now IWDB can tell you how much genetic influence that ancestor has on your own dog.

We have added quite a lot of health data to the database. These are public records containing results from screening programs. We are making progress in opening up for user-submitted data, but aren’t quite there yet.

Types of data

Most of the screening results fall into one of four categories:

Hips or Hip Dysplasia (HD)

Elbows or Elbow Dysplasia (ED)

Heart/Cardiac

Eyes

In addition there is some data on Patella Luxation (PL), Spondylosis, Thyroid levels, and some other problems, but the bulk of our data fall into one of the top categories.

Hips and Hip Dysplasia

There are numerous ways to annotate data on hip dysplasia. If the result is seen as a single letter, it’s the worst grade of the two hip joints. The scale is as follows:

A: No signs of Hip Dysplasia

B: Near Normal Hip Joints

C: Mild Hip Dysplasia

D: Moderate Hip Dysplasia

E: Severe Hip Dysplasia

This scoring-system is used throughout most FCI-countries. However, in the US, Canada, Switzerland, UK, Ireland, Australia and New Zealand other systems are used. The US and Canada use the OFA-scoring mode, whereas the UK, Ireland, Australia and New Zealand use what’s called the BVA/KC-scoring mode. In Germany a more finetuned version of the FCI-system is used. You may read more on these different scoring modes in this excellent article.

For comparision, we’ve put together the following table:

FCI

UK, AU, NZ

Switzerland

USA (OFA)

A

0-3

0-2

Excellent and Good

B

4-8

3-6

Good and Fair

C

9-18

7-12

Borderline and mild

D

>18

13-18

Moderate

E

>18

19-24

Severe

In some older screening systems, the grade NR is also recorded, meaning No Remark, which would be similar to A or Excellent.

Elbows and Elbow Dysplasia

For elbows and elbow dysplasia, systems have become much more standardised over the last few years. While Elbow Dysplasia can mean a number of different things, the systems used throughout the world grades elbow dysplasia according to this:

Some countries will grade both elbows separately. You will then see scores for each elbow (0/1 for example), while others only list the worst elbow without further information (2 for example). You may occasionally see NR used on older elbow-tests as well. That means No Remark, transforming to grade 0.

Heart and Cardiac

While there are established systems in place for hips and elbows, the territory for heart problems and the cardiac system is more unclear. First off, there’s numerous ways to examine a canine heart. Most breed bodies recommend a composite check, consisting of ausculation, ElectroCardioGram (ECG) and EchoCardioGram (Cardiac Ultrasound). There are several methods to evaluate these results. There’s some consensus across Europe to use the Vollmar-protocol for evaluating results, except for Great Britain where a separate UK-scheme is used. In the US, the screening results recorded by OFA are more varied, but to our knowledge, full tests are done when results are marked with Cardiologist, Echo.

Eyes

You will know there are a number of eye diseases that can affect a dog. The screening result will display what disease (if any) was found. For checks of type Eyes (CERT) and a result which is a number, the number indicates which year the eyes were certified to be fine. If there are any remarks here, they will explain what was wrong.

Why do we need pedigrees at all? We sometimes meet with people who don’t use pedigree information in their breeding and some don’t see the point in pedigrees or indeed pedigree dogs. So we had a long thought about the whole point of pedigrees and creating things like iwdb.org.

A dog’s blueprint

The pedigree is the blueprint from which a dog is created. With proper knowledge of the dogs appearing in the pedigree, it’s quite possible to have a good mental approximation of what the final result of any mating are likely to be. That goes for looks, mentality, potential for longevity andrisk of diseases.

Of course, nothing’s certain when it comes to genetics. Everything’s governed by probabilities, but at least you have a good chance of altering the odds in your favour by using good pedigree data.

The article also mentions Anne Janis’ free and excellent risk assessment. She uses pedigree data extensively together with information – often given to her in strict confidentiality to calculate the risk of diseases like PRA.

Documenting our history

Did you know that the Irish wolfhound is being considered for enrolment in UNESCO’s World Heritage list? Many of us believe the breed is a vital part of the Irish heritage and as such the world heritage. Yes, it’s that important. Without pedigrees, we wouldn’t have any history to point at, and the Irish wolfhound would just be considered any big dog. With pedigrees, we can all trace the history of our dogs back to the few remaining Irish wolfhounds in the mid 19th century. Most dogs in iwdb.org has pedigrees going back that far. These data are an enormously important part of the breed history.

Making sure we are on the right track

Geneticists can tell us what we should do (Don’t inbreed, keep the effective population size high, breed for health and longevity). Without pedigrees, there’s no way we can actually do that. Think of iwdb.org as the Icelandic dating app which will help you make sure your bedpartner isn’t genetically unsafe. We provide tools that help breeders do what’s best for the breed and breed bodies to keep an eye on what’s happening. Without pedigrees, it would all be impossible.

All these things are equally true for other pedigree breeds as well. They may not have as good a tool as we have (although some have), but we are getting there. There’s also inititatives going on between the various international kennel clubs to make an international, all breeds, complete database. That probably won’t happen in the next few decades, though.

What’s in a dog’s name and what can it tell us? Since the 1920’s it has been common to use kennel names, so a dog’s name may consist of a kennel name and then a given name. It’s not given that all dogs bred by that specific breeder carries his or her kennel name. In many countries there are, or has been, limitations on approving kennel names, so even very reputable breeders may have started out creating litters with no kennel name. Kennel names are in general strictly controlled in order to avoid that two breeders carry the same kennel name.

In most countries, it’s forbidden to have more than one kennel name in a dog’s name. This is done to avoid confusion about who the breeder actually is. This doesn’t apply to Australia, UK, Canada and USA, where you’ll often see two kennel names in the pedigree name. This will normally happen when a dog is sold from one kennel to another, and the new one appends it’s own kennel name to the existing name, but may also happen in other situations. In certain countries you may also see breeders using other breeders’ kennel names in naming their own dogs.

In many cases, breeders will choose to name all siblings in a litter within a particular theme, often that will be a common first letter in their given names. This is completely voluntary, but gives a good indication on who a certain dog is sibling to. In USA, it will often be up to the owner to give the dog a new, registered name, and in many cases the littermates have no resemblance in name.